1. Field
The presently disclosed subject matter relates to headlight controllers, optical units and vehicle headlights, and more particularly to vehicle headlights including the headlight controller and the optical unit, which do not include a movable component with a simple structure, and a vehicle headlight having a favorable light distribution pattern that can be easy to drive at night, while preventing the optical unit from emitting a glare-type light to oncoming vehicles and vehicles moving forward on a driving lane in response to various traffic conditions.
2. Description of the Related Art
When drivers steer a car at night, the drivers usually want to steer the car while they turn on headlights for a high beam to improve a visibility. However, drivers must drive the car while they switch between the headlights for a high beam and headlights for a low beam in response to various traffic conditions so that the headlights do not give a glare type light to oncoming vehicles, vehicles moving forward on a same driving lane, etc.
Hence, vehicle headlights including an adaptive driving beam (ADB) have been developed. A vehicle headlight including an ADB, for example, may contribute an improvement of visibility in a forward direction of the vehicle that has the ADB for a driver by detecting an oncoming vehicle, a forward vehicle and the like with a camera incorporated into the vehicle that has the ADB and by emitting a high beam for the driver on an area except regions where the oncoming vehicle and the forward vehicle move.
A first conventional headlight controller for an ADB is disclosed in Patent Document No. 1 (Japanese Patent Application Laid Open JP 2011-31807). FIGS. 23a to 23f are schematic light distribution patterns depicting light distributions with respect to horizontal line H and vertical line V, which may be formed by the first conventional headlight controller used in countries where drivers keep to the left side of the road. FIG. 23a shows a light distribution pattern Lo for a low beam, which may prevent emission of a glare type light to an oncoming vehicle moving on the right side of the road. FIG. 23b shows a light distribution pattern Hi for a high beam, which may emit light toward an innermost region in a forward direction of the vehicle using the headlight controller.
FIG. 23c shows a light distribution pattern LHi for a left half high beam, in which the headlight controller combines a left half high beam distribution pattern formed by a left headlight with a low beam distribution pattern formed by a right headlight. This light distribution pattern LHi may be useful where vehicles moving forward on the same driving lanedo not exist and an oncoming vehicle approaches the vehicle on an oncoming lane. FIG. 23d shows a light distribution pattern RHi for a right half high beam, in which the headlight controller combines a right half high beam distribution pattern formed by the right headlight with a low beam distribution pattern formed by the left headlight. The light distribution pattern RHi may be useful where vehicles do not exist on the oncoming lane and a vehicle moves forward on the same driving lane.
FIG. 23e shows a light distribution pattern V to inhibit light close to an intersection of horizontal line H and vertical line V, in which the headlight controller combines a low beam distribution pattern formed by the left headlight with a low beam distribution pattern, which is symmetric with respect to the vertical line V of the low beam distribution pattern of the left headlight, formed by the right headlight. The light distribution pattern V may allow ease of recognition of an obstacle close to either road shoulders while preventing a glare-type light from being emitted to a faraway vehicle.
FIG. 23f shows a split light distribution pattern S, in which the headlight controller combines a left half high beam distribution pattern swiveled leftward by the left headlight with a right half high beam distribution pattern swiveled rightward by the right headlight. The light distribution pattern S may improve visibilities out of the driving lane and the oncoming lane while preventing the left and right headlight from emitting a glare type light to an oncoming vehicle and a vehicle moving on the same driving lane.
FIG. 24 is a block diagram showing the first conventional headlight controller for the ADB, which is described with reference to FIGS. 23a to 23f, and a second conventional headlight controller, which adds a dotted line region into the block diagram of the first conventional headlight controller shown in FIG. 24 as described later. The above-described right and left headlight 210 includes: a bulb 14 emitting light in a direction toward a light-emission of the headlight 210; a leveling actuator 226 moving the bulb 14 in a vertical direction toward the light-emission of the headlight 210; a swivel actuator 222 moving the bulb 14 in a horizontal direction toward the light-emission of the headlight 210; a shade motor 221 rotating a revolution shade that shades the light emitted from the bulb 14; a driving circuit 230 turning on the bulb 14; and a lighting controller 228 controlling the driving circuit 230, the leveling actuator 226, the swivel actuator 222 and the shade motor 221, and thereby forming the above-described light distribution patterns.
The first conventional headlight system 100 including the right and left headlight 210 further includes: a light switch 304 selecting either manual mode or ADB mode that forms the above-described light distribution patterns based upon traffic conditions; a camera 306 detecting the traffic conditions such as an oncoming vehicle, a vehicle moving forward on a driving lane and the like, and outputting such data to a vehicle controller 302; a steering sensor 308 detecting a wheeling angle of the subject vehicle, and outputting data of the wheeling angle to the vehicle controller 302; a speed sensor 310 detecting a traveling speed of the subject vehicle, and outputting the traveling speed data to the vehicle controller 302; and a navigation system 312 obtaining road information and the like, and outputting such data to the vehicle controller 302; and the vehicle controller 302 providing the lighting controller 228 in the headlight 210 with information for forming the light distribution patterns to in accordance with the above-described various data, as the headlight controller.
In the first conventional headlight system 100, when a vehicle using the headlight system 100 inclines in a longitudinal direction thereof, because a sight of the camera 306 incorporated into the vehicle varies, locating information of the traffic conditions such as an oncoming vehicle, a vehicle moving forward on its driving lane and the like, which are photographed by the camera 306, may also vary. Accordingly, when the vehicle inclines in the longitudinal direction thereof due to an uphill, an downhill and the like, the first conventional headlight system 100 may not prevent the headlight 210 from emitting a glare type light to the oncoming vehicle, the vehicle moving in a forward direction of the light emitting vehicle, etc.
Hence, a second conventional headlight system, which adds the dotted line region into the block diagram of the first conventional headlight system 100 shown in FIG. 24, is disclosed in Patent Document No. 2 (Japanese Patent Application Laid Open JP 2011-31808). The second conventional headlight system further includes: an inclined angle sensor 316 detecting an inclined angle of the subject vehicle with respect to the horizontal line H; a vehicle height sensor 314 detecting a pitch angle of the subject vehicle; a memory 318 storing data for the camera 306 such as a distortion of a lens, etc; and thereby the vehicle controller 302 calculating a correction data, so that the headlight system can form the light distribution patterns such that prevent the headlight from emitting a glare type light to oncoming vehicles, vehicles travelling in the forward direction of the subject vehicle and the like, even when the subject vehicle inclines.
Therefore, the second conventional headlight system may prevent the headlight 210 from emitting a glare type light to an oncoming vehicle, a vehicle moving in the forward direction of the subject vehicle and the like, even when the subject vehicle inclines in a longitudinal direction thereof due to the downhill, etc. However, an illuminating area where the headlight 210 may prevent giving a glare type light to the oncoming vehicle, the vehicle moving in the forward direction of the subject vehicle and the like, may vary each in cases that the vehicle takes a straight line, takes a right turn, takes a left turn, etc.
In addition, when a vehicle moving in the forward direction of a subject vehicle changes lanes, when the vehicle moving in the forward direction of the subject vehicle moves in a horizontal direction of the subject vehicle, and the like, the illuminating area where the headlight 210 may prevent giving a glare type light to the oncoming vehicle and the like, may vary from a case where the subject vehicle takes a straight line along with the vehicle moving forward on a same driving lane. That is because the oncoming vehicle and the vehicle moving forward on the same driving lane may frequently change in the horizontal direction of the subject vehicle using the headlight 210.
Moreover, the conventional headlight 210 includes movable parts such as the leveling actuator 226, the swivel actuator 222, the revolution shade rotated by the shading motor 221 and the like, and therefore may be subject to a complex structure. Furthermore, it may be very difficult to reduce a size of the headlight 210 because of the movable parts, and also may be difficult to design headlights having an attractive outside appearance such that matches various vehicular designs because the movable parts may limit a possibility of headlight design.
The above-referenced Patent Documents and additional Patent Documents are listed below and are hereby incorporated with their English abstracts and specification in their entireties.    1. Patent Document No. 1: Japanese Patent Application Laid Open JP 2011-31807    2. Patent Document No. 2: Japanese Patent Application Laid Open JP 2011-31808    3. Patent Document No. 3: U.S. patent application Ser. No. 13/229,663    4. Patent Document No. 4: U.S. patent application Ser. No. 12/720,819    5. Patent Document No. 5: U.S. patent application Ser. No. 13/083,522    6. Patent Document No. 6: Japanese Patent Application Laid Open JP 2011-221371
The disclosed subject matter has been devised to consider the above and other problems, characteristics and features. Thus, exemplary embodiments of the disclosed subject matter can include headlight controllers which can provide a favorable light distribution pattern to safely drive at night in accordance with various traffic conditions, while preventing a right and left headlight from giving a glare type light to oncoming vehicles and vehicles moving in a forward direction of a subject vehicle, even when the vehicle moving in the forward direction of the subject vehicle changes lanes, and even when the vehicle moving in the forward direction of the subject vehicle moves in a horizontal direction of the subject vehicle.
In addition, exemplary embodiments of the disclosed subject matter can include optical units with a simple structure, which can be used as the right and left headlight for the above-described headlight controller. The optical units do not include movable parts such as the conventional headlight, and therefore can expand possibilities for design so as to be able to harmonize with various vehicular designs.